Manufacturing method of piezoresistive acceleration sensor based on son structure

Abstract

The invention discloses a manufacturing method of a piezoresistive acceleration sensor based on a SON structure, and belongs to the technical field of microelectronic fabrication. The method comprisesthe following steps of depositing an epitaxial silicon germanium layer on a silicon substrate; forming a cavity range pattern and a corrosion blocking trench in the silicon germanium layer; forming an SiO2 oxide layer in the corrosion blocking trench; depositing an amorphous silicon layer to obtain a sensitive film; forming a corrosion through hole on the amorphous silicon layer; depositing a silicon dioxide layer and a silicon nitride layer; forming a rectangular corrosion cavity in the silicon germanium layer; removing the silicon dioxide layer and the silicon nitride layer of the amorphoussilicon layer; injecting P+ ions and P- ions into the amorphous silicon layer to form a force-sensitive resistor; depositing a silicon oxide dielectric layer; forming metal wires and metal PAD dots on the surface of the silicon oxide dielectric layer; and forming a sensitive film release structure corresponding to the inner sides of both long sides of the rectangular corrosion cavity. The dampingeffect of the piezoresistive acceleration sensor during the measurement process can be significantly reduced, and the measurement accuracy of the piezoresistive acceleration sensor is improved.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of microelectronics fabrication, and in particular to a fabrication method of a piezoresistive acceleration sensor based on a SON structure. Background technique [0002] According to different working principles, MEMS acceleration sensors can generally be divided into piezoelectric, piezoresistive, capacitive servo, etc. The production processes of different types of MEMS acceleration sensors are also different. [0003] In the manufacture of conventional MEMS piezoresistive acceleration sensors, the sensitive layer needs to be bonded to silicon and silicon, but silicon-silicon bonding will inevitably produce bonding stress, which will lead to errors in the measurement of piezoresistive acceleration sensors. Contents of the invention [0004] In order to solve the problems in the prior art, an embodiment of the present invention provides a method for manufacturing a piezoresistiv...

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Problems solved by technology

[0003] When the conventional MEMS piezoresistive acceleration sensor is manufactured, the sensitive layer needs to be bonded with silicon and silicon, but silicon-silicon bonding will inevitably produce bonding stress, which will cause errors in the measurement of the piezoresistive acceleration sensor

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